Submission #815741

#	Time	Username	Problem	Language	Result	Execution time	Memory
815741		exodus_	Ekoeko (COCI21_ekoeko)	C++14	20 / 110	49 ms	4728 KiB

Main

#include<bits/stdc++.h>
using namespace std;
int freq[200];
const int maxn = 200001;
vector<char>exclnt;
deque<int>dex[200];
vector<int>ord;
int segtree[4*maxn]={0};
void update(int idx, int low, int high, int val) {
    if(low==val && high==val) {
        segtree[idx]=1;
        return;
    }
    if(val<low || val>high) {
        return;
    }
    int mid = (low+high)/2;
    update(2*idx,low,mid,val);
    update(2*idx+1, mid+1,high,val);
    segtree[idx] = segtree[2*idx] + segtree[2*idx+1];
}
int quer(int idx, int low, int high, int l, int r) {
    if(low>=l && high<=r) {
        return segtree[idx];
    }
    if(low>r || high<l) return 0;
    int mid = (low+high)/2;
    return quer(2*idx,low,mid,l,r)+quer(2*idx+1,mid+1,high,l,r);
}
int main() {
    int n;
    string gab;
    cin >> n;
    cin >> gab;
    n = n*2;
    for(int i=0; i<n; i++) {
        int x = gab[i]-97;
        freq[x]++;
    }
    for(int i=0; i<n; i++) {
        int x = gab[i]-97;
        if(freq[x] > 0) {
            exclnt.push_back(gab[i]);
            freq[x]-=2;
        }
    }
    int ukex = exclnt.size();
    for(int i=0; i<ukex; i++) {
        exclnt.push_back(exclnt[i]);
    }
    for(int i=0; i<n; i++) {
        int x = exclnt[i]-97;
        dex[x].push_back(i);
    }
    for(int i=0; i<n; i++) {
        int x = gab[i]-97;
        ord.push_back(dex[x].front());
        dex[x].pop_front();
    }
    int ans=0;
    for(int i=0; i<n; i++) {
        ans+=quer(1,1,n-1,ord[i],n-1);
        update(1,1,n-1,ord[i]);
    }
    cout << ans << endl;
    return 0;
}

• Subtask 1: 0 / 10
• Subtask 2: 0 / 20
• Subtask 3: 0 / 20
• Subtask 4: 20 / 20
• Subtask 5: 0 / 40